The development of the scientific ideas of I. P. Pavlov on the goal reflex in studies of the mechanisms of biological motivation.

Data obtained in experimental studies developing I. P. Pavlov's concept of the "goal reflex" are presented. It is shown that purposive behavior in the systems organization of behavioral acts is constructed by the dominant motivation. This article discusses mechanisms determining the energy of biological motivations and their controlling component--the results of action acceptor. The role of reinforcement in the mechanisms forming molecular engrams of behavior on structures of the results of action acceptor is assessed.